The present invention relates to a circle cutter, particularly to an instrument adapted for cutting circles on objects. It includes a rotary disc assembly and a cutting tool. The rotary disc assembly is made up of an outer ring board, a rotary disc, a fixing ring cap and a plurality of beads. The rotary disc mounted to the outer ring board is movably limited in place by the fixing ring cap and are rotatably supported by the multiple beads received in a tunnel defined between the outer ring board and the rotary disc. On the rotary disc are disposed a plurality of holes marked with a numeral that is the diameter of a circle to be cut. The cutting tool has a hollow pen stick and a cutting knife attached to a knife clip that is movably engaged with a holding head. The holding head is further secured to the bottom end of the hollow pen stick and is free to rotate with respect to the pen stick so that the cutting knife can be smoothly guided in a cutting operation.
The circle cutter of the present invention is placed on top of an object in use, and a cutting tool is selectively engaged with a hole on the rotary disc which is made to rotate by the cutting tool so that a circle area can be cut on the object by a cutting knife mounted to the cutting tool.
In general, to cut circles on various kinds of paper, thin cardboard and soft thin wood board, circles of proper sizes are first drawn on them by a compass and then a pointed knife is used to cut along a drawn line a circle. Such a conventional way of cutting circle is tedious and time consuming in one aspect; and so obtained circles are not smooth and precise enough in another aspect. Besides, accidental cutting can often result in damage to the used material.